Liviproveiviemt in  dental chairs



2 Sheets-Sheet 1f. S. S. WHITE. l DENTAL CHAIR.

Patente-d, Feb. 20,1877.

WITNESSES N.PETERS, PHOT0LITHOGRAFHER WASHINGTDNfQ C:

Unrrrnn r @Errea SAMUEL S. VHITE, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN DENTALICHAERS.

Specilication forming part of Lettere Patent No. lS7,5'3, dated February 20, 1577; application filed January 15,1877.

To all ywhom 'it may concern: i

' Be it known that I, SAMUEL S. Wnrrr., of the city and county ot' Philadelphia, and State of Pennsylvania, have invented certain new and useful Improvements in Dentists Chairs,

of which theV following is a specifica-tion:

M y invention relates to a dentists chair, the various parts of which are adjustable to suit lthe varying conditions Vunder which it is required to work, and resembles in its general features and constitutes an improvement upon the chair patented tot). G. White, July 30, 1872, No. 130,093, and reissued July 11,1876, as No. 7,223. V

rlhe object ofthe first part of my invention is `to render variable the angle ot' inclination of the chairframe and seat relatively to the base upon which it is mounted, which end I attain by pivoting the frame upon its support through a step ot' which a screw works vertically, and has its upper end journaled in a pivoted plate near the front of the chair-frame, said screw being rotated by suitable means to vary the inclination of the frame, as will hereinafter more fully appear. l

'lhe object of the next part of my invention is to provide a backrest capable of heilig raised o r lowered relatively to the chair-frame, and also of being adjusted to or from its support to render the position of the occupant more easy or firm, which ends I attain by hinging the upper end of a back-rest to a telescoping section or tube adjustable vertically in the chair-frame, the lower end of which section carries a screw to adjust the lower end ot' the bacl-1est to or from its support, as will hereinafter more fully appear.

My invention further has for its objects to furnish a dental chair generally more availa; ble and reliable in its adjustment than those heretofore constructed, which ends I attain in the manner hereinafter specically set forth.

The subjectmatter claimed will hereinafter specilically be designated.

In the accompanying drawings, which represent all my improvements as embodied in a single chair in the best Way now known to me, Figure l represents a vertical central section through my improved chair on the linel l of Fig. 2. Fig. 2 represents a similar section therethrough on the line 2 2 ot' Fig. l; and

Fig. 3 represents a detached sectional view, on an enlarged scale, ot' the peculiarlyconstrnctedfadjusting-screw of the back-rest, taken on the line 3 3 of Fig. 2.

rIhe base or stool A-is provided with an inL tornally-threaded tube, B, a screw-shaft, U, and a sliding sleeve, D, enveloping both the tube and screw-shaft, substantially as shown and described in O. U. NVhites patent, above mentioned, and as this means of raising and lowering the chair-frame constitutes no part of my invention it is deemed unnecessary to describe-,it more fully.

The chair-frame E rocks or is pivoted upon i arms extending from the turning and endwisemoving sleeve or support D, as in said pa'tent, and, in order to vary the inclination ot' the chair-frame relatively to its base, and hold it in any desired position, the sleeve D is provided with a step, D', in which is journaled a block, d', through which a screw, F, works, the upper end of said screw being journaled so as to lturn freely, but is prevented from endwise movement in a pivoted plate, Gr, near the front of the chair-frame, and carries uppn said end a bevel-wheel,f, driven by a corresponding bevel-gear, It, on a winch-shaft, H, turning in bearings on the plate G, as clearly shown in Fig. 2.

By this mode of construction I secure a positive and secure means ot' inclining the chai-r in any position.desired, the screw, pivoted plate, and winch-shaft yielding to accommodate its movement.

The seat or cushion otl the chair slides in guides, which permit it to move in and out horizontally, and the guides are curved up slightlyat their forward ends, so as to elevate the front ot' the seat as it moves forward. The dotted lines in Fig. 1 indicate this adjustment.

The footrest frame l moves in guides in pendent arms El of the chair'frame, and is adjusted in a manner and by means substantially similar to that shown and described in the patent of O. C. White aforesaid, and, therefore, need not be particularly shown or described by me.'

The back or frame of the chair is provided with a tube, E2, in which slides or telescopes another tube or section, I', carrying a back rest or Support, J, hinged or pivoted toits upper end, a suitable set-screw, t', locking the sections together at any point desired.

In order to render this back rest capable of being adjusted to or from its support to increase the ease and com fort or the firmness of position of the occupant, inaddition to its capabilities ot being raised and lowered independently of the chair-frame, its lower end is hinged to a screw, K, working within a threaded socket, k1, journaied so as to turn freely, but prevented from endwise movement in a rocking bearing, 7a2, mounted in thelower end ot' the telescoping section I', the section or tube E2 being slotted at e, to permit of the free passage ot' the adjusting-screw and its socket when the backrest is heilig adjusted up 0r down.

By rotating the threaded socket k1 by means ofa proper handle at the back of the chair, the lower end ot' the back-rest is adjusted toward or from the chair-back proper through the medium of the screw K working in said socket, whose bearing is free to yield to ac commodate its movement. The telescoping section is shown in this instance as a tube, in which a rod, L, supporting a head-rest of any approved construction slides freely, and is locked in any position desired by a set-screw, l. The head-rest shown in this instanceis one substantially similar in construction and 0p= eration to that shown in the Letters Patent granted to Eli T. Starr, December 28, 1875, as No. 171,539, and consequently needs no detailed description here.

The operation and advantages ot' my improvements will be obvious from the foregoing description.

I claim as of my own invention- 1. The combination, substantially as herein before set forth, of the base or stool, a support adjustable thereon, the chair-frame rocking on the support, a screw working in said support and havingits upper end journaled in a pivoted plate on the chair-frame, and gea-ring for operating said screw, whereby the inclination ot' the chair-frame relatively to the base upon which it is mounted may be varied.

2. The combination, substantially as hereinbet'ore set forth, of the chair-frame, its tnbular portion, the section telescoping therewith carrying a hinged back rest or support, and a screw also carried by said section, whereby the back-rest is capable ot' being adjusted both vertically and to and from its support.

In testimony whereof I have hereunto subscribed my name.

. SAMUEL S. WHITE.

Witnesses J. A. B. WILLIAMS, FRANK L. HrsE. 

